Hi Mika, On Tue, Jun 9, 2015 at 5:51 AM, Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> wrote: > On Mon, Jun 08, 2015 at 02:50:28PM -0300, lucas.de.marchi@xxxxxxxxx wrote: >> From: Fabio Mello <fabio.mello@xxxxxxxxx> >> >> According to documentation and tests, initialization is not >> necessary on module resume, since the controller keeps its state >> between disable/enable. Change the target address is also allowed. >> >> So, this patch replaces the initialization on module resume with a >> simple enable, and removes the (non required anymore) enables and >> disables. >> >> Signed-off-by: Fabio Mello <fabio.mello@xxxxxxxxx> >> Signed-off-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx> >> --- >> >> These pictures explain a little more the consequence of letting the >> enable+disable in the code: >> >> http://pub.politreco.com/paste/TEK0011-before.jpg >> http://pub.politreco.com/paste/TEK0007-after.jpg >> >> The yellow line is a GPIO toggle in userspace to mark when we start and finish >> the i2c transactions. The blue line is the SCL in that i2c bus. Take a look on >> the huge pauses we have between any 2 transactions. These pauses are removed >> with this patch and we are able to read our sensor's values in 950usec rather >> than 5.24msec we had before. We are testing this using a Minnowboard Max that >> has a designware i2c controller. > > Did you test this on any other platform than Intel Baytrail? No. The only soc we have here with this controller is the Baytrail. -- Lucas De Marchi -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
